The invention relates to a tube coupling system for spindles of spinning or twisting machines, where at least one radial bore hole is provided in a spindle upper part, into which bore hole a centrifugal body with a cylindrical area is set, the centrifugal body being prevented from falling out by a shoulder on a corresponding opposite surface of the spindle upper part, and being provided with a coupling surface on its front side.
In the case of a tube coupling system of this kind (British patent 10 90 354), the spindle upper part is provided with a longitudinal bore hole with a relatively large diameter. There are at least three radial bore holes in the wall of the hollow cylindrical spindle upper part, arranged equidistant over the circumference of the spindle upper part. In each bore hole a mainly cylindrical centrifugal body is set, which has a shoulder enlarged in diameter towards the axis of the spindle upper part, so that the centrifugal body cannot fall out during operation. The preferred number of three centrifugal bodies are set into the corresponding radial bore holes from the inside, through the axial bore hole of the spindle upper part during assembly. The axial bore hole is then closed with a cap, the cap projecting deeper into the axial bore hole by means of a cylindrical extension so that the centrifugal bodies can rest against the extension when the spindle is not in operation. When the spindle is in operation, the centrifugal bodies, by means of the centrifugal forces, move so far outwards that the coupling surface on the front side of the centrifugal bodies rests on the inner wall of the attached tube.
Apart from the fact that the putting on of a cap to close the axial bore hole of the spindle upper part brings with it the danger of a state of unbalance, the production and assembly costs for the tube coupling system are relatively high. Besides the three radial bore holes, which must be exactly equidistant from each other on the circumference, an exactly aligned axial bore hole has to be provided. The setting up of the centrifugal bodies from the inside of the spindle upper part requires a certain amount of skill.
An object of the invention is to make a tube coupling system which is easy to produce and assemble and where the danger of unbalance is small.
This object is achieved according to preferred embodiments of the invention in that the shoulder in the area of the coupling surface and the opposite surface in the area of the outer circumference of the spindle upper part is configured so the diameter towards the bore hole radial outer end is smaller.
According to the invention, production therefore is confined to placing the radial bore holes at the given places and setting the mainly cylindrical centrifugal bodies into them. In a mass production, very small permissible variations can be maintained, and the danger a state of unbalance is small. The diameter of the bore hole on the outer circumference of the spindle upper part is reduced slightly during the assembly of the centrifugal bodies, just so much that an opposite surface for the shoulder is formed so that the centrifugal bodies cannot spin off during operation when a tube is not attached. The reduction of the diameter is however small enough to allow the centrifugal bodies with their coupling surface to move far enough out of the radial bore hole to hold a tube.
The opposite surface, on which the shoulder of a centrifugal body rests, is preferably formed by means of plastic deformation of the spindle upper part. This deformation can be effected by caulking or crimping the spindle upper part with the centrifugal body.
With regard to the manufacture for this plastic deformation during assembly, it is practical when the shoulder of the centrifugal body is formed as a conical stopping face. The coupling surface itself is for this purpose convex, so that the centrifugal body with its curvature can overhang the radial bore hole sufficiently and thus create the coupling with the tube.
In a particularly advantageous development of the invention, the bore hole is formed as a through bore hole, in which two retractable centrifugal bodies are set, the centrifugal bodies lying diametrically opposite each other on the outer circumference of the spindle upper part. The providing of a through bore hole at right angles to the axis of the spindle upper part is particularly easy to do, and the danger of a state of unbalance is significantly smaller than if only bottom holes for the centrifugal bodies were to be used. Two centrifugal bodies can be set in a single through bore hole, which then also have exactly the same distance between angles in circumferential direction of the spindle upper part. The danger of a state of unbalance is therefore very small. The length of the centrifugal bodies is such that they do not project out of the spindle upper part when the spindle is not operating. For this purpose the length of the centrifugal bodies is approximately the same as the radius of the spindle upper part so that the centrifugal bodies in the area of the axis of the spindle upper part can be arranged alongside one another. When in operation, the coupling surfaces of the two diametrically opposed centrifugal bodies project sufficiently far out of the through bore holes.
In a further advantageous development of the invention it is provided that two through bore holes, slightly out of line with each other in the axial direction of the spindle upper part, are set at right angles to each other. In this way, four coupling points are created, on which the coupling surfaces of the centrifugal bodies can rest on the inner wall of the tube.
Centrifugal clutches in general have a great advantage in that the coupling effect is increased with increasing spindle revolutions, that is, the effect is particularly great when it is actually most needed. When the spindle is at a standstill, however, no centrifugal forces are at work and therefore no pressure, so that tubes can be placed easily on the relevant spindle upper part without having to overcome coupling forces.
In a process to assemble the tube coupling system of the invention, the following procedure is carried out: first, a peg of a tool, axially supported, is set into the through bore hole, the peg having an appropriate stopping face of the shape and operational position of the shoulder of a centrifugal body. Then a first opposite surface is created through pressure on the stopping face by means of a stamp. The peg is then removed from the bore hole and both centrifugal bodies are set in their place. Finally, the centrifugal body, facing away from the first opposite surface, is brought into its operational position by means of a supporting plug to be placed on the side of the first opposite surface, and, by means of the above-mentioned stamp, the second opposite surface is created through pressure applied to the shoulder of the relevant centrifugal body. Further advantages and features of the invention will become apparent from the following description in conjunction with the accompanying drawings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.